Low Fecundity Research Articles

Quantifying microplastics concentration of invertebrates from three Antarctic fjords.

Microplastics, small pieces of plastic measuring less than five millimeters, have spread to all ecosystems, even those in the Southern Ocean around Antarctica. In particular, microplastics have been found contaminating water in emerging fjords, or inlets created by deglaciation, along the Antarctic Peninsula. Microplastics contamination puts fjord communities, which are unique and dominated by benthic species, at high risk for microplastic exposure leading to issues with feeding, endocrine disruption, and exposure to adsorbed toxins, all of which lower fecundity and survivability. The objective of this study was to quantify microplastics in invertebrates grouped according to feeding type. Invertebrates were collected from the Western Antarctic Peninsula fjords during 2017 and 2020 from three fjords via a mini-Agassiz trawl to quantify microplastic concentrations and identify polymer composition using Micro-ATR-FTIR. In 2017, 2.39 microplastics individual-1 were identified, while 5.01 microplastics individual-1 were identified in 2020. Out of the 24 polymers and polymer associates identified, the most common polymers were polypropylene, polycarbonate, polyamide, and polystyrene. Overall, the most common microplastic color category was black/brown/gblay, and fragments were the most common shape identified. Microplastics presence was significantly higher in the invertebrate organisms compared to procedural blanks (p<0.001), but feeding mechanism was not found to be a predictor of microplastic bioaccumulation. Microplastics concentrations in invertebrates differed between fjords in 2017 (p=0.010) but not in 2020. Complementing previous research on microplastics in Southern Ocean fjordic water, this study reveals new evidence of microplastics in Antarctic fjordic inhabitants.

Age, growth, and intrinsic sensitivity of Endangered Spinetail Devil Ray (Mobula mobular) and Bentfin Devil Ray (M. thurstoni) in the Indian Ocean

AbstractDevil rays (Mobula spp.) are caught in fisheries across the Indian Ocean, with reports of significant recent declines in catch and sightings. Globally, the few populations studied have extremely low population growth rates due to low fecundity and long reproductive cycles, making them highly vulnerable to overfishing. To allow for assessment of the current sustainability of devil ray catch in the Indian Ocean, we provide estimates of age using the caudal vertebrae; somatic growth using a Bayesian, multi-model approach; maximum intrinsic rate of population increase (rmax); and fishing mortality for Endangered Spinetail Devil Ray (Mobula mobular) and Bentfin Devil Ray (M. thurstoni) sampled from small-scale fisheries catch in Indonesia, Kenya, and Pakistan. The oldest individuals of Spinetail Devil Ray (n = 79) and Bentfin Devil Ray (n = 59) were 17.5 and six years, respectively. Both species had relatively low growth coefficients (k = 0.05 and g = 0.19 year−1, respectively), with the von Bertalanffy and logistic models providing the best fitting growth models, and low rmax (0.109 and 0.107 year−1, respectively) indicating that they are highly sensitive to overexploitation. Fishing mortality F estimates (0.16 and 0.18 year−1, respectively) were higher than rmax and exploitation ratio E (0.77 and 0.80, respectively) were higher than an optimum value of 0.5 for biological sustainability for both species, suggesting that the fisheries catches of the species are unsustainable. We demonstrate an approach to assess data-poor species and apply this to two Indian Ocean devil ray species. The results highlight the urgent need for better management actions to reduce the catch of all devil rays to prevent species extinction and aid in population recovery.

Overfishing of Threatened Bycatch Species in a Marine Protected Area: The Elasmobranchs of Banc d'Arguin, Mauritania

ABSTRACTElasmobranch (rays and sharks) populations are vulnerable to overexploitation due to their slow growth, late maturity, and low fecundity. Industrial fishery impacts on sharks and rays are known, whereas impacts of artisanal fisheries are less understood. We quantified catches of sharks and rays in artisanal fisheries at the Parc National du Banc d'Arguin (Banc d'Arguin), Mauritania (West Africa) during 1998–2020, a period when fishing effort increased around 2006, catches increased, but catch‐per‐unit‐effort declined substantially. Shark nets and meagre fixed gill nets were used to catch elasmobranchs, with catches comprising over 60% of elasmobranch species. Therefore, elasmobranchs were not bycatch, but rather, the target of fisheries. Of 33 elasmobranch species captured, 94% of shark species and 76% of ray species are threatened with extinction. We recommend that management approaches should focus on fishing locations with the highest occurrence of threatened elasmobranch species in catches, through new regulations on fishing gear types and discouragement of trade in elasmobranch products from Banc d'Arguin.

Molecular dissection of laboratory contamination between two schistosome populations

BackgroundGenomic analysis has revealed extensive contamination among laboratory-maintained microbes including malaria parasites, Mycobacterium tuberculosis, and Salmonella spp. Here, we provide direct evidence for recent contamination of a laboratory schistosome parasite population, and we investigate its genomic consequences. The Brazilian Schistosoma mansoni population SmBRE has several distinctive phenotypes, showing poor infectivity, reduced sporocyst number, low levels of cercarial shedding and low virulence in the intermediate snail host, and low worm burden and low fecundity in the vertebrate rodent host. In 2021 we observed a rapid change in SmBRE parasite phenotypes, with a 10-fold increase in cercarial production and fourfold increase in worm burden.MethodsTo determine the underlying genomic cause of these changes, we sequenced pools of SmBRE adults collected during parasite maintenance between 2015 and 2023. We also sequenced another parasite population (SmLE) maintained alongside SmBRE without phenotypic changes.ResultsWhile SmLE allele frequencies remained stable over the 8-year period, we observed sudden changes in allele frequency across the genome in SmBRE between July 2021 and February 2023, consistent with expectations of laboratory contamination. (i) SmLE-specific alleles increased in the SmBRE population from 0 to 41–46% across the genome between September and October 2021, reflecting the timing and magnitude of the contamination event. (ii) After contamination, strong selection (s ≅0.23) drove the replacement of low-fitness SmBRE with high-fitness SmLE alleles. (iii) Allele frequency changed rapidly across the whole genome, except for a region on chromosome 4, where SmBRE alleles remained at high frequency.ConclusionsWe were able to detect contamination in this case because SmBRE shows distinctive phenotypes. However, this would likely have been missed with phenotypically similar parasites. These results provide a cautionary tale about the importance of tracking the identity of parasite populations, but also showcase a simple approach to monitor changes within populations using molecular profiling of pooled population samples to characterize single-nucleotide polymorphisms. We also show that genetic drift results in continuous change even in the absence of contamination, causing parasites maintained in different labs (or sampled from the same lab at different times) to diverge.Graphical

Evidence for a gut microbial community conferring adaptability to diet quality and temperature stressors in phytophagous insects: the melon fruit fly Zeugodacus cucurbitae (Diptera: Tephritidae) as a case study

BackgroundThe high invasiveness of phytophagous insects is related to their adaptability to various environments, that can be influenced by their associated microbial community. Microbial symbionts are known to play a key role in the biology, ecology, and evolution of phytophagous insects, but their abundance and diversity are suggested to be influenced by environmental stressors. In this work, using 16 S rRNA metabarcoding we aim to verify (1) if laboratory rearing affects microbial symbiont communities of Zeugodacus cucurbitae females, a cosmopolitan pest of cucurbitaceous crops (2) if temperature, diet quality, and antibiotic treatments affect microbial symbiont communities of both laboratory and wild populations, and (3) if changes in microbial symbiont communities due to temperature, diet and antibiotic affect longevity and fecundity of Z. cucurbitae.ResultsThe results showed that microbial diversity, particularly the β-diversity was significantly affected by insect origin, temperature, diet quality, and antibiotic treatment. The alteration of gut microbial symbionts, specifically Enterobacteriaceae, was associated with low fecundity and longevity of Z. cucurbitae females feeding on optimal diet only. Fecundity reduction in antibiotic treated females was more pronounced when flies were fed on a poor diet without protein.Conclusionsour study proves the relationship between gut microbiome and host fitness under thermal and diet fluctuation highlighting the importance of microbial community in the adaptation of Z. cucurbitae to environmental stress.Clinical trial numberNot applicable.

Zebrafish Research Model: Homeopathy in Heavy Metal Intoxication

Environmental contamination by heavy metals is a significant global concern due to its adverse impacts on human, animal, and ecosystem health. Heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) are particularly worrying because of their persistence in the environment and toxic potential. These metals can be found in water bodies, affecting the quality of drinking water and aquatic ecosystems. Exposure to these metals through water can cause acute and chronic poisoning, damage to kidneys, liver, and nervous system, and increase the risk of cancer. Homeopathic medicines have great potential for treating intoxications and have been demonstrated clinically; however, other medicines still need to be tested. Zebrafish (Danio rerio) is used to study the toxicity of hazardous chemicals, including the assessment of impacts on reproductive, cardiovascular, and neural development, making it a relevant model to explore the efficacy and safety of homeopathic treatments. Studies on arsenate, mercury, and lead intoxication using the aquatic model have shown that homeopathic medicines (Arsenicum album, Mercurius solubilis, and Plumbum metallicum) reduced anxiety as well as physical and neurological effects caused by fish intoxication. The advantages of using Zebrafish as a research model include small size and low maintenance cost, rapid development, high fecundity, and external reproduction, as well as sequenced genome and genetic similarity to humans. This makes Danio rerio a model used worldwide.

Relative fecundity and ploidy of 34 Buddleja cultivars

Abstract Buddleja davidii (butterfly bush) is a popular landscape plant that is also an invasive species in Oregon and other temperate locations. In Oregon, the plants are classified as a class B noxious weed (which enacts a ban on the species within state lines), with exemptions to the ban based on fertility data or interspecific pedigree alone. To date, there is no evidence that suggests all interspecific hybrids of butterfly bush exhibit reduced fecundity that would lower invasive potential. This study investigates what correlation, if any, there is between interspecific hybridization and lowered fecundity in butterfly bush as well as the cytogenetic effects of interspecific hybridization in the genus. Relative fecundity of 34 Buddleja cultivars of mixed pedigree was analyzed with three populations: the cultivars in a study field, a greenhouse population for controlled crossing, and an open pollinated population generated from cultivars. Interspecific cultivars were consistently both within the highest range of fecundity as well as the lowest range, with greenhouse crossing generally supporting field findings. Flow cytometry conducted on cultivars revealed lower than expected variation in genome size. This study shows interspecific hybridization does not appear to guarantee reduction in fecundity. Species used in this study: butterfly bush Buddleja davidii L.

Toward the Development of the Trojan Female Technique in Pest Insects: Male-Specific Influence of Mitochondrial Haplotype on Reproductive Output in the Seed Beetle Acanthoscelides obtectus.

Biocontrol techniques that impair reproductive capacity of insect pests provide opportunities to control the dynamics of their populations while minimizing collateral damage to non-target species and the environment. The Trojan Female Technique, or TFT, is a method of the trans-generational fertility-based population control through the release of females that carry mitochondrial DNA mutations that negatively affect male, but not female, reproductive output. TFT is based on the evolutionary hypothesis that, due to maternal inheritance of mitochondria, mutations which are beneficial or neutral in females but harmful in males can accumulate in the mitochondrial genome without selection acting against them. Although TFT has been theoretically substantiated, empirical work to date has focused only on Drosophila melanogaster populations, while the existence of male-biased mutations and the TFT approach in economically important pest species remain unexplored. Here, we examined the sex-specific effects of three distinct and naturally occurring mitochondrial haplotypes (MG1a, MG1d, and MG3b) on several reproductive and life history traits in the seed beetle Acanthoscelides obtectus. Our results revealed that males harboring the MG3b mitotype exhibited lower early fecundity and fertility, while there were no effects on females or longevity in either sex. Our experiments provide support for the existence of the mitochondrial variant that specifically impairs male reproductive output in pest insects. These results can be harnessed to further develop TFT as a novel form of biocontrol with broad applicability to economic pests and disease vector insects.

Assessment of Controlled Spawning Practices and Female Broodstock Replacement on Reproductive and Production Metrics in Culture of Gourami (Osphronemus goramy)

Gourami (Osphronemus goramy) is a freshwater fish species that has gained significant popularity among consumers due to its economic value and high nutritional content. However, various challenges in aquaculture have led to an imbalance in gurami production, influenced by factors such as low fecundity, fertilization rates, hatching success, and a limited spawning season that occurs only from February to July. Outside of this period, the spawning performance of gourami tends to decline. Consequently, it is essential to implement effective spawning manipulation techniques to enhance seed production in gurami aquaculture, particularly through controlled spawning methods that involve the replacement of female broodstock post-spawning to improve production outcomes. This study examines the production performance of controlled spawning (with broodstock replacement) versus uncontrolled spawning (without broodstock replacement) to fecundity, fertilization rates, hatching success, and the productivity of spawning containers. The research employs two treatments with three replications each: controlled and uncontrolled spawning. The findings indicate no significant differences (P&gt;0.10) between controlled and unchecked spawning regarding fecundity, hatching success, fertilization rates, and spawning container productivity. Thus, it can be concluded that there are no significant differences in outcomes between the two treatments, suggesting that both methods can be effectively utilized.

Function Analysis of Heme Peroxidase Genes, MpPxd2 and MpPxd4, Under Thiacloprid Exposure in the Neonicotinoid-Resistant Myzus persicae (Sulzer).

The green peach aphid, Myzus persicae, is a notorious pest worldwide. We collected a field population of the pest (FZQ-F) that exhibited high resistance to neonicotinoids. Exposure to neonicotinoids can induce oxidative damage in animals; however, it remains unclear whether antioxidant enzymes contribute to the innate immune response of neonicotinoid-resistant pests against high doses of insecticides. Treatment with sublethal doses of thiacloprid (LC10 and LC25) for 3, 6, 12, 24, 48, and 72 h resulted in significantly increased reactive oxygen species (ROS), including H2O2 content, in FZQ-F adults, indicating insecticide-induced oxidative stress. Additionally, the peroxidase activity in FZQ-F adults increased after thiacloprid exposure. Using comparative genomics, we identified 31 heme peroxidases in M. persicae with a typical "2Cys" structure, and phylogenetic analyses divided them into five groups. Comparative transcriptomes revealed that MpPxd2 and MpPxd4 were significantly upregulated in thiacloprid-treated aphids. Thiacloprid exposure significantly induced MpPxd2 and MpPxd4 expression levels, consistent with high H2O2 content and peroxidase activity. The knockdown of MpPxd2 or MpPxd4 in FZQ-F increased their susceptibility to imidacloprid, thiacloprid, and thiamethoxam, verifying the protective role of the heme peroxidases against neonicotinoids in aphids. The knockdown of MpPxd2 or MpPxd4 also led to shorter longevity and a low fecundity of adult aphids at 31 °C compared to controls. The results show that MpPxd2 or MpPxd4 is important in how cells respond to oxidative stress and may help resistant M. persicae pests to handle neonicotinoids.

Effect of wheat cultivars, with varying resistance levels to Rhyzopertha dominica, on life history parameters of the ectoparasitoid wasp Anisopteramalus calandrae

The ectoparasitoid wasp Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), as a widely distributed ectoparasitoid wasp, can parasitize several Coleopteran insect pests such as the lesser grain borer Rhyzopertha dominica (F.) (Coleoptera, Bostrichidae). In the current study, the plant-herbivore-parasitoid interactions with A. calandrae and R. dominica on six cultivars of wheat Triticum aestivum L. (Poals: Poaceae), including Aftab, Araz, Ghabos, Kalateh, Meraj, and Tirgan, were assessed. The largest egg and larval-pupal periods of R. dominica were observed on cultivars Tirgan and Aftab. Rhyzopertha dominica reared on cultivar Araz had the largest total developmental period. The highest oviposition period and fecundity of R. dominica were observed on cultivar Meraj. The pest had the brief life and the low fecundity duration on cultivar Tirgan. The longest developmental time of A. calandrae was observed on the cultivar Tirgan. The parasitic wasp lived longer on cultivar Ghabos. The developmental time of A. calandrae was positively affected by phenolic content of wheat cultivars. The fecundity and intrinsic rate of increase (r) of the parasitic wasp were significantly decreased by increasing the phenolic content of the cultivars. In general, the cultivar Meraj was sensitive, the cultivars Aftab and Kalateh were semi-resistant, and the cultivars Araz, Ghabos, and Tirgan were resistant to R. dominica. The cultivar Tirgan was found as an unsuitable host compared to others for performance of A. calandrae, while Aftab, Kalateh, Araz, and Meraj were suitable ones. Consequently, the use of cultivar Araz as a resistant host to R. dominica and the suitable cultivar to A. calandrae can be considered as an effective integrated management choice against the pest.

Contribution of disease to Australian sea lion (Neophoca cinerea) pup mortality at Seal Bay, Kangaroo Island, 2016–2022

AbstractThe endangered Australian sea lion (Neophoca cinerea) population is declining, and its conservation is threatened by the species' low fecundity and high pup mortality. This study details reasons for pup deaths and quantifies the impacts of disease and comorbidity. Of 284 dead pups reported from five breeding seasons (2016–2022) at the Seal Bay colony, Kangaroo Island, gross necropsy was conducted on 122, with fecal analysis for hookworm (Uncinaria sanguinis) detection, tissue histology, and bacterial culture performed on subsets. Determinable primary causes of mortality were conspecific trauma (± comorbidity, 41.0%), starvation (24.6%), and infectious disease (hookworm‐associated hemorrhagic enteritis [HAHE] ± bacterial infection, 19.7%). Allowing for comorbidity, 37.7% of pups died with an infectious disease, including 44.0% of deaths with trauma and 41.5% with starvation. In higher mortality summer‐autumn breeding seasons, pups were at greater risk of trauma (p = .001) and subsequent bacterial infection (p &lt; .001). Parasiticide treatment significantly reduced HAHE‐associated (p = .005) and overall mortality (p &lt; .001) risk, suggesting hookworm infection increases pup susceptibility to other causes of mortality. Although the exact causal pathways for this treatment‐related overall mortality benefit remain to be confirmed, intervention appears highly impactful and could benefit species conservation efforts.

Past and recent drivers of extinction risk in endemic New Zealand birds

AbstractLand‐cover change is a major driver of species extinction risk and the overarching loss of biodiversity. However, the impact of such change is nuanced, varying among species due to the mediation of life‐history traits and the timing of land transformation. While diverse studies have pinpointed ecological and life‐history attributes linked to the decline of bird species, the combined effects of past and recent land‐cover change often present a complex picture. In this study, we undertook a modelling approach to assess extinction risk in New Zealand's endemic birds based on life‐history traits and past (1996–2008) and recent (2008–2018) land‐cover change. Our results suggested specific variables driving extinction risk in endemic New Zealand birds. Notably, incubation length emerged as the most influential factor, trailed by past land‐cover change, body size and clutch size. This indicates that past land‐cover change in combination with large body sizes and slow life histories, characterized by low fecundity and extended incubation periods, collectively elevates the extinction risk of endemic birds in New Zealand. These results shed light on the conservation priorities for species with specific biological traits potentially exposed to the negative effects of land‐cover change.

Population Expansion but Limited Gene Flow in Kuhl's Blue‐Spotted Maskray Along the Tanzanian Coast

ABSTRACTThe blue‐spotted maskray Neotrygon kuhlii (Müller &amp; Henle, 1841) is a member of the Dasyatidae family of stingrays which grows slowly. Members of this group mature late and have a low fecundity rate. The ICUN Red List of Threatened Species lists N. kuhlii species as data deficient (DD) because information on its ecology and life history is not readily available. The purpose of this study was to determine the genetic diversity, demographic history and population structure of N. kuhlii, all of which are critical information for efforts aimed at conserving the species. The investigation was carried out along Tanzania's coastline using 595 base pairs of partial mitochondrial cytochrome oxidase subunit I (COI) sequence. The haplotype diversity ranged between 0.37 and 0.70 and nucleotide diversity between 0.11% and 0.50%. The findings show that samples from Unguja had higher mean molecular diversity indices than those from other sampling sites. Nonetheless, samples from Mafia and Unguja were found to have the largest effective population size. Genetic variations were found between the subpopulations under study, suggesting limited genetic connectivity among the studied subpopulations. The COI sequences of N. kuhlii from most subpopulations studied showed signs of past population expansion, which are typical for most Western Indian Ocean (WIO) fauna. The findings highlight the need for enhanced management and conservation strategies for N. kuhlii and other coastal stingray species in Tanzania, particularly in areas where sampling sites showed low levels of genetic diversity and effective population size.

Cumulative effects of mutation accumulation on mitochondrial function and fitness

The impact of mutations on the mitochondria deserves specific interest due to the crucial role played by these organelles on numerous cellular functions. This study examines the effects of repeated bottlenecks on mitochondrial function and fitness. Daphnia pulex mutation accumulation lines (MA) lines were maintained for over 120 generations under copper and no copper conditions. Following the MA propagation, Daphnia from MA lines were raised under optimal and high temperatures for two generations before assessing mitochondrial and phenotypic traits. Spontaneous mutation accumulation under copper led to a later age at maturity and lowered fecundity in the MA lines. Mitochondrial respiration was found to be 10% lower in all mutation accumulation (MA) lines as compared to the non-MA control. MtDNA copy number was elevated in MA lines compared to the control under optimal temperature suggesting a compensatory mechanism. Three MA lines propagated under low copper had very low mtDNA copy number and fitness, suggesting mutations might have affected genes involved in mtDNA replication or mitochondrial biogenesis. Overall, our study suggests that mutation accumulation had an impact on life history traits, mtDNA copy number, and mitochondrial respiration. Some phenotypic effects were magnified under high temperatures. MtDNA copy number appears to be an important mitigation factor to allow mitochondria to cope with mutation accumulation up to a certain level beyond which it can no longer compensate.

Transcriptional and physiological plasticity of the green peach aphid (Hemiptera: Aphididae) to cabbage and pepper plants.

Defensive metabolites and nutrient restriction of host plants are 2 major obstacles to the colonization of insect herbivores. The green peach aphid (GPA) Myzus persicae (Sulzer) broadly colonizes plants with diverse nutritional and defensive traits. However, how GPA adapts to nutritional and defensive traits within different plants remains largely unknown. To elucidate this, we first investigated the performances and transcriptomes of GPA feeding on cabbage Brassica oleracea and pepper Capsicum annuum. The green peach aphid had lower weight and fecundity when feeding on cabbage than on pepper. The transcriptomic analysis found 824 differentially expressed genes (DEGs), and 13 of the top 20 Kyoto Encyclopedia of Genes and Genomes pathways are related to nutrient metabolism, energy metabolism, and detoxification. Specifically, we found 160 DEGs associated with the metabolism of protein and amino acids, sugar and lipids, and xenobiotic substances, 86 upregulated in cabbage-fed GPA. Fourteen cathepsin B genes were strongly upregulated in cabbage-fed GPA, and were enriched in lysosome pathway and 2 dominated gene ontology terms peptidase activity and proteolysis. In addition, cabbage-fed GPA upregulated sugar and lipid digestion, while downregulated lipid biosynthesis processes. Furthermore, 55 metabolic detoxification enzyme genes were differentially expressed between GPA on 2hosts, and detoxification enzyme activities of GPA indeed changed accordingly to the host. Then, we found that cabbage has lower amino acids nutrition quality for GPA compared to pepper. Our results suggested that adjustment of nitrogen nutrient metabolism, sugar and lipid metabolism, and metabolic detoxification in a host-specific manner play crucial roles in the adaptations of GPA to different host plants.

Whole genome resequencing analysis elucidate genetic features and signature of selection in binhu buffaloes

The world's buffaloes are primarily divided into two main categories: swamp buffaloes and riverine buffaloes. Binhu buffaloes (BB) are Chinese indigenous swamp buffaloes, characterized as strong body vigor, fit for durable work with docile nature. However, there is literature void regarding genomic architecture and selective sweeps analysis for this breed. Herein we utilized 20 newly whole genome sequences (WGS) of BB together with published WGS data of seventy-four buffaloes [Upper Yangtze (UY) buffaloes; n = 30, Middle-Lower Yangtze (MLY) buffaloes; (n = 30) and River buffaloes (RB); (n = 14)] to elucidate population structure, genetic diversity and selection characteristics of the BB. The results showed that the BB originated from swamp buffalos. The genetic diversity of the BB was lower than that of the RB and higher than that of the UY and the MLY buffaloes. In addition, employing five selective sweep detection methods numerous genes related to immunity (RELT, TP73, C5, CHMP1A, CDK10, ANKRD17), heat tolerance (DNAJB4, DNAJA1, HSF4, HELB, DNAJC28), growth (LYN, DYNC1I2, PLAG1, ADAMTSL3, CHKB, PDE1A, RXFP2), carcass and metabolism (SIRT6, LYPLA1, FADS1), nervous system (KIRREL3, AUTS2), and reproduction (SMG6, TSNAXIP1, CACNB2, ERCC3, RAD51, GDF9, CAMK4, KALRN, FANCA, SPIRE2, ATP2B1, AREG, EREG) were found to be under selection. Taken together, current investigation provides a genetic basis for the characteristics specific to the BB, such as high body strength; tolerance to roughage and easy to gain weight; docile nature; ability to endure labor; strong adaptability; and low fecundity and offers new ideas for the conservation, development and utilization of this breed.

Effect of Chlorantraniliprole on Life History Traits and Relative Fitness of Laboratory-Selected Resistant and Susceptible Populations of Spodoptera litura (Lepidoptera: Noctuidae).

Insecticides are widely used to control pests and improve agricultural yield. The use of indiscriminate amounts and persistent pesticides has not only resulted in insect pest resistance challenges but has also harmed non-target organisms and contaminated the environment. We assessed the cost-effectiveness of Spodoptera litura (Fabricius) resistance to chlorantraniliprole (CTPR) as part of insect resistance control programs. S. litura larvae were collected from the fields and treated with chlorantraniliprole for 15 generations. Compared to the unselected population (Unsel-Lab), the chlorantraniliprole-selected population (CTPR-Sel) of S. litura exhibited a resistance level of 98.23 times. The findings demonstrated that the chlorantraniliprole-resistant genotype had lower egg-to-adult survivability, longer egg-to-adult developing times, and lower fecundity than the chlorantraniliprole-susceptible genotype. Compared to the Unsel-Lab population, the CTPR-Sel population of S. litura had a poorer relative fitness (0.44) at LC30 and shorter male/female longevity. Demographic parameters, including net reproductive rate (R0) and intrinsic (rm) and finite rate of increase (λ), were lower in the CTPR-Sel strain than in Unsel-Lab S. litura. These findings demonstrate that chlorantraniliprole resistance in S. litura has fitness costs at the individual and population levels, implying that removing the selecting agent from the environment might result in less resistance and opportunities for susceptibility restoration. As a result, the current work could help to determine effective management strategies to prevent chlorantraniliprole resistance in S. litura.

The life (history), diet and death of the blackspot shark (Carcharhinus sealei) from South-east Asia

Context The blackspot shark (Carcharhinus sealei) is a small-bodied coastal shark often incidentally caught in fisheries across South-east Asia. Aims This study aimed to document the species’ biology, ecology, fisheries and markets to inform conservation. Methods In total, 103 blackspot sharks from Indonesia (n = 101) and Singapore (n = 2) were examined to determine biological parameters (growth rate, age at maturity, reproductive traits and diet). An interview with a Singaporean seafood supplier gave insight to population trends, fisheries and markets. Key results Males attained a maximum age of 9 years, the smallest mature individual measured 709-mm stretched total length (STL), with 50% reaching maturity at 6.15 years. Females attained a maximum age of 11 years, the smallest mature individual measured 730 mm STL, with 50% reaching maturity at 6.12 years. The species has an overall growth rate (k) of 0.37 year−1. Reproduction was asynchronous, with only two pups produced per litter. Crustaceans dominated the diet of juveniles, whereas bony fishes and cephalopods dominated the diets of adult males and adult females respectively. Conclusions Blackspot sharks have a moderately fast growth rate, but a late age-at-maturity and a low fecundity. Diet differed between the sexes as well as adults and juveniles. Implications The low fecundity and late maturity of blackspot sharks increase their vulnerability to exploitation. Blackspot sharks are now listed on CITES-Appendix II, but mortality may remain high because they are reportedly often caught incidentally.

Membrane progesterone receptor γ (paqr5b) is essential for the formation of neurons in the zebrafish olfactory rosette

Paqr5b is a gene encoding membrane progesterone receptor γ (mPRγ), which is one of five mPR subtypes. Paqr5b belongs to the progestin and adipoQ receptor (PAQR) family, which consists of 11 genes. To elucidate the physiological functions of the mPR subtypes, we established gene knockout (KO) zebrafish strains by genetically editing seven paqr genes and analyzed their phenotypes. The null-mutant strain of paqr5b (paqr5b−/−) that we established in this study showed low fecundity, reduced chorion elevation and a high percentage of abnormal embryos. Embryos showed curvature of the spine and an abnormal head morphology. Individuals with abnormal head morphology continued to develop a phenotype of markedly abnormal palatine bone. The length of the brain of paqr5b−/− zebrafish was short, and the position of the cerebellum moved to the front and overlapped with that of the midbrain. Micro-CT scans revealed that the olfactory rosettes (ORs) were so shrunken that they were difficult to identify and connected with the olfactory bulbs (OBs) by thread-like structures. Immunohistochemical staining of OR with an anti-Paqr5b antibody revealed that Paqr5b was extensively expressed in neurons in the OR in wild-type zebrafish, whereas signals were not detected in paqr5b−/− zebrafish. In histological sections, the neurons disappeared, and the lamellar layer of the OR became thinner. These results indicate that Paqr5b is required for the formation of neurons in the OR. This is the first report demonstrating a distinct role for the mPR gene.